Automatic stove



May 17, 1949.

A. e. THOMAS 2,470,533

AUTOMATIC STOVE Filed March '7, 1945 T qa o O I Patented May 17, 1949 UNITED STATES PATENT OFFICE AUTOMATIC STOVE Albert G. Thomas, Alexandria, Va.

Application March 7, 1945, Serial No. 581,361

3 Claims.

This invention relates to draft regulators of the automatic type and paticularly to devices of this class which are adapted to control the draft supplied to wood-burning or other stoves.

An object of my invention is to provide a draft regulator having direct and positive action as distinguished from devices of this class which are characterized by a multiplication of toggles, links, levers, etc.

Another object of this invention is to provide a draft regulator which is responsive to exceedingly slight temperature gradients and is yet rugged and dependable in operation.

An additional object is to provide an automatic stove having a draft regulator operated by an elongated bimetal element placed beneath the stove.

Other objects and advantages will appear as this description proceeds.

Reference is now had to the drawings wherein like parts are indicated by the same reference numerals and wherein Figure 1 is a side elevation view, partly in section, of a preferred form of my invention, and

Figure 2 is a partial view of the upper front of the stove of Fig. 1.

In Fig. 1 I have shown an elongated bimetal member 35 subject to air circulating beneath the stove I and having operating connection with a flap valve located at the lower end of a down draft passageway. An elongated channel member 91) is suitably secured to the wall of the stove l to form the downdraft passageway 30 communicating with combustion chamber opening 29. The latter is closed by flap valve 3| pivoted at 32 to a plate 33 bolted to stove I as shown in Fig. 1. A right angular portion of flap valve 3| engages the head of a vertical plunger 34 having a lower end resting upon one end of an elongated bimetal strip 35 whose remote end is mounted at 36 upon the bottom of the stove. It will be observed that the bimetal strip 35 is spaced from the bottom of the stove for the major portion of its length. It may be preferable to shield the bimetal 35 from the direct heat of the bottom of the stove. A sheet of material of poor heat conductivity or a heat reflector having a polished surface will serve this purpose as will be understood. The bimetal can be mounted on a heat insulating support fastened to the stove. The construction embodied in Fig. 1 utilizes an inexpensive downdraft pipe and at the same time incorporates a thermostatic bimetal which is directly responsive to the temperature condition at the coldest stratum of air in the room.

Figure 2 shows the manner of fastening channel 9b to the stove.

It will be apparent that many changes may be made in the illustrated form of my invention which has been described in the foregoing without departing from the principles of my invention. Furthermore, the bimetal or other thermostat may be placed on a wall of the room or remote from the stove and the valve can be operated by links, cables, or other means, electrical, pneumatic or mechanical. Therefore, I desire that my invention be limited only by the subjoined claims.

I claim:

1. In a stove, an air duct connected with an opening in a wall of said stove, a flap valve for said opening pivoted to said stove adjacent the lower part of said valve, an arm extending from said valve and tending by means of its weight to assist in moving said valve in a direction away from said opening, a substantially vertically movable element adapted when lifted to strike said arm to move said valve in a direction toward said opening, and an elongated bimetal element attached adjacent one end thereof to said stove beneath a bottom surface thereof, said vertically movable element being associated with said bimetal element adjacent the other end thereof to cause movement of said valve toward said opening upon rise of temperature of said bimetal element.

2. Same as in claim 1 and including bearing means for said vertically movable element.

3. In a stove, an air duct connected with an opening in a wall of said stove, said air duct having integral portions bent and apertured to serve as bearings, an element substantially vertically slidable in said apertures, a flap valve pivoted to said stove in said duct and movable to regulate the draft through said wall opening, an arm extending from said valve adjacent the pivot thereof and tending by means of its weight to move said valve away from said opening, said arm resting upon a top surface of said vertically slidable element, an elongated bimetal element attached adjacent one end thereof to said stove beneath a bottom surface thereof, the lower end of said vertically slidable element resting upon said bimetal element adjacent the other end thereof.

ALBERT G. THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,170,728 Montague Aug 22, 1939 2,199,875 Brogden May 7, 1940 2,273,418 Prince Feb. 17, 1942 2,294,032 Hoch Aug. 25, 1942 2,309,295 Barnes Jan. 26, 1943 2,388,829 Cheasley Nov. 13, 1945 FOREIGN PATENTS Number Country Date 3,523 Great Britain 1913 49,568 Sweden Aug. 22, 1917 

